Field of the Invention
This invention relates to a process and apparatus for finish grinding splines or gear teeth on a workpiece. More specifically, the invention involves a process and apparatus for grinding workpieces having high dimensional accuracy requirements and includes a device for determining the cross sectional shape of the grinding wheel which is used to control the sharpening of the wheel.
High-precision grinding machines are known in the art and typically have a grinding wheel with at least the peripheral portion having a desired cross-sectional shape. Each time the grinding wheel contacts the workpiece, a portion of the wheel is worn away, which changes its dimensions. The known devices have included means for monitoring the dimensions of the grinding wheel and also include sharpening devices to sharpen and shape the wheel between grinding operations. When the wheel has become significantly worn, it must be replaced.
French Patent 2,517,237 illustrates a grinding apparatus that is automatically controlled by a computer device. This apparatus includes a grinding device with a grinder wheel, which is automatically controlled by the computer.
U.S. Patents to Barth et al. (U.S. Pat. Nos. 4,295,301 and 4,359,841) disclose a process and an apparatus for dressing or sharpening a grinding wheel which is controlled by a device that detects the wear of the wheel by a contact sensor.
The U.S. Patent to Himmel (U.S. Pat. No. 4,158,507) as well as European Patent 0195405 disclose systems for monitoring the contours of workpieces utilizing a laser beam light source.
The known systems have not been able to achieve the required accuracy of monitoring the shape of the grinding wheel without undully delaying the grinding operations. These systems have been found inadequate to finish grind splines or teeth on workpieces that must be formed with extremely close tolerances as required in such workpieces intended for aeronautical applications.